Problem: The points $(9, -5)$ and $(-3, -1)$ are the endpoints of a diameter of a circle. What is the sum of the coordinates of the center of the circle?
Solution: The center of the circle is located at the midpoint of any diameter. Thus, the center of the circle is $\left(\frac{9+(-3)}{2}, \frac{(-5)+(-1)}{2}\right) = (3, -3)$. The sum of the coordinates of the center of the circle is therefore $3 + (-3) = \boxed{0}$.